Castor: an old crop with new potentials

Thousand of years ago, oil from the seed of the castor plant was used as a fuel for wick lamps. Presently it is used in many products including skin ointments, sunburn lotions, hair tonics, laxatives, and cosmetics. And now a new use is being developed.

"Castor is an ideal candidate for production of high value biomass because it has 48 percent to 60 percent seed-oil content, and potential oil production of up to 220 gallons per acre," says Dick Auld, Rockwell Professor at Texas Tech University in Lubbock. "And another plus for castor oil is it will produce 4 to 8 calories of liquid fuels per calorie invested in production and processing.

"Furthermore, because castor is not used for food or feed, and can be grown productively on marginal lands, this crop represents a unique opportunity to expand biomass production in this area and in the country as a whole," Auld said.

Historically, domestic production of castor has been limited by concerns about its toxins and allergens, lack of agronomic information necessary for commercial production, and a shortage of varieties adapted to potential production sites in the United States.

Auld says these concerns are being addressed by a consortium of federal and university scientists who have submitted a grant proposal on genetically improving varieties, and designing appropriate cropping systems for castor across the United States.

Texas Tech University has developed a new, experimental variety of castor variety with reduced levels of toxins that will be named “Brigham” in honor of Dr. Ray Brigham, a retired Texas A&M scientist who was an early pioneer in castor genetics. Additionally, geneticists at TTU are developing germplasms for improved productivity and drought tolerance from lines selected from diverse germplasm sources, in comparison to commercial varieties, from both the United States and Brazil. With this germplasm pool, they will combine genes into advanced castor lines that will have reduced levels of toxins and allergens, increased oil yields, and broader environmental adaptability.

On the cropping systems front, Steve Oswalt, research associate at Texas Tech University, is evaluating two varieties for oil production under five levels of drip irrigation. Also, cropping-systems agronomists from six universities across the United States have agreed to conduct variety adaptation and plant population studies, which will facilitate commercial production of castor if grant funding is obtained.

"Results from the efforts of the consortium will be far reaching," says Auld. "The increased production of castor oil in the United States should reduce the need to import both castor and petroleum, provide an additional crop for rural growers, and provide an opportunity to revitalize older and smaller storage, crushing, and processing facilities abandoned by food-oil-crop processors for newer, more centrally located facilities." Initially, the production of castor biomass feedstocks will target the United States market for biodiesel. "Diesel represents 20 percent of the United States transportation fuel, and replacement of even 5 percent of this petroleum-based diesel demand with biodiesel would require between 12 and 14 million acres of castor to produce the 2.5 billion gallons of castor oil needed," Auld said.

"In addition to the biodiesel market, a nearly unlimited potential market exists for castor oil biomass because it can be used as a feedstock to produce lower molecular weight aviation fuels, fuel additives, and biopolymers."